The Human Impact Flashcards
What was the CO2 concentration pre-industrial and what is it now?
The CO2 concentration was 280 ppm pre-industrial and is now 420 ppm in 2024.
How much has the CO2 concentration increased in the last 200 years?
There has been a 50% increase in CO2 concentration in the last 200 years.
What effect does CO2 and H2O have on radiation?
CO2 and H2O let incoming shortwave radiation in but trap outgoing longwave radiation, re-radiating it back to the Earth.
What evidence is there for climate change?
Evidence includes extreme heat waves, increasing wildfires, and melting glaciers.
What is the Keeling Curve?
The Keeling Curve shows the overall trend of increasing CO2 ppm since 1958.
What does HadCRUT5 measure?
HadCRUT5 measures global average temperature change.
How much has the world temperature increased since 1850?
The world temperature has increased by over 1.5°C since 1850.
What is the impact of a 1°C increase in air temperature?
A 1°C increase in air temperature means it can store 7% more water.
How do ocean temperature changes compare to land?
Oceans heat up much less than land, with changes 3-4 times lower than temperature increases.
What has happened to Arctic sea ice since 1979?
The amount of Arctic sea ice has decreased significantly, with the Arctic becoming 13.3% smaller every decade.
What is the ice albedo positive feedback loop?
Ice reflects a lot of incoming insolation, but if it melts, darker ground absorbs more insolation, increasing temperatures.
How much have sea levels risen since pre-industrial levels?
Sea levels have risen by 30 cm since pre-industrial levels.
What are the main causes of sea level rise?
Melting terrestrial ice and thermal expansion of water as it heats up.
What was the hottest decade in the 20th century?
The 1990s was the hottest decade in the 20th century.
What did the 1997 Kyoto Protocol aim to achieve?
It aimed to reduce greenhouse gas emissions to 5.2% below 1990 levels over the period 2008-2012.
What percentage of greenhouse gas emissions is CO2?
76% of emissions are CO2.
What is the atmospheric lifetime of methane?
Methane has an atmospheric lifetime of 9-15 years.
What is the primary greenhouse gas contributing to climate change?
Carbon dioxide (CO2) is the primary greenhouse gas.
How much CO2 is released by human activities annually?
Human activities currently release over 50 gigatons of CO2 into the atmosphere every year.
What percentage of global greenhouse gas emissions does the food industry account for?
The food industry accounts for roughly a quarter of total global greenhouse gas emissions.
What is the impact of urban areas on local climates?
Urban areas modify temperature, precipitation, humidity, and wind.
What is an urban heat island?
An urban heat island is a localized area that experiences higher temperatures than surrounding rural areas.
How much more rainfall occurs in London compared to surrounding areas?
Up to 25% more rainfall occurs in London compared to surrounding areas.
What effect do tall buildings have on wind in urban areas?
Tall buildings can channel wind and create an ‘urban canyon’ effect, increasing local wind speeds.
What happens during a temperature inversion in cities?
Pollution gets trapped in a city, creating thick smog.
What is the effect of the Venturi Effect on local wind speeds?
Local speeds are higher due to the Venturi Effect, creating turbulence and abrupt changes in wind direction and speed, increasing the frequency of turbulent winds.
How do urban areas compare to rural areas in terms of average wind speeds?
Urban areas experience slower average wind speeds compared to rural areas, which may see higher velocity winds.
What happens to pollution in the presence of strong prevailing winds?
Strong prevailing winds can blow pollution to the side, creating a pollution plume.
What are pollution domes and when do they occur?
Pollution domes occur during a temperature inversion, trapping pollution in a city and creating thick smog.
What is smog and how does it form?
Smog occurs when particulate matter mixes with fog under a temperature inversion.
How does increased heat affect smog formation?
Increased heat enhances photochemical reactions, increasing airborne particles and contributing to smog and cloud formation.
How much less sunlight does London receive compared to the surrounding countryside?
London receives approximately 279 fewer hours of sunlight than the surrounding countryside due to clouds and smog.
What is photochemical smog?
Photochemical smog is formed through a chemical reaction involving sunlight, nitrogen oxides, and volatile organic compounds (VOCs), resulting in airborne particles and ground-level ozone.
What pollutants contribute to photochemical smog?
Pollutants such as nitrogen oxides, sulphur oxides, and hydrocarbons are released by fossil fuels.
How does UV light affect pollutants in the atmosphere?
UV light causes pollutants to break down into harmful chemicals, such as ozone, which forms photochemical smog.
What are some pollution reduction policies?
Pollution reduction policies include clean air acts, vehicle control in urban areas (e.g., congestion charge in London), public transport improvements, and more environmentally friendly or electric public transport.
